Clues to non-organic sensory symptoms in neurology
C Sen1, K Chatterjee2,
1 Department of Medicine, Medical College, Kolkata, West Bengal, India
2 Dr. R.M.L. Hospital, New Delhi, India
Department of Medicine, Medical College, Kolkata, West Bengal
|How to cite this article:|
Sen C, Chatterjee K. Clues to non-organic sensory symptoms in neurology.J Postgrad Med 2013;59:341-342
|How to cite this URL:|
Sen C, Chatterjee K. Clues to non-organic sensory symptoms in neurology. J Postgrad Med [serial online] 2013 [cited 2020 Aug 11 ];59:341-342
Available from: http://www.jpgmonline.com/text.asp?2013/59/4/341/123189
The article regarding the usefulness of the Hoover's sign in a routine neurological examination brings to the forefront the commonly encountered but less dwelled upon patient of functional neurological deficit.  Functional symptoms, not consistent with any recognized structural or pathophysiological abnormalities, account for about one third of patients presenting to the neurology outpatient clinic.
In physical examination, the Hoover's sign has been widely studied for functional motor weakness. Several studies exist, validating its repeatability, ease of application, and sensitivity in detecting a non-organic weakness, but what to do when encountered with a patient with inexplicable sensory symptoms?
Based on history, it has been observed that the larger the number of presenting symptoms, the more likely it is that the primary illness is a functional one. Associated symptoms like depersonalization and derealization may occur in a functional patient as well as some cases of epilepsy or migraine. Social history is relevant, though one should be cautious to not oversimplify the situation by attributing all symptoms to a single stressor. Probing about psychological symptoms should be left till the end of history taking, in order to not make the patient defensive in fear of being dismissed as "psychiatric", as observed by Reuber et al. 
A number of ways for detecting functional sensory loss have been cited in literature. In this letter, we would like to recollect some of the methods to detect a functional sensory deficit. ,
La belle indifference - an apparent lack of concern for the symptoms or its implications, usually described in relation with conversion disorder. The fallacies in this symptom are that the patient may consciously pretend being cheerful in order to not be stamped as depressed, or the patient may be feigning the symptoms and hence not be concerned with them. Therefore, this test does not have much significance.Demarcation of limb - the patient may have sensory symptoms in a limb, limited at the groin or shoulder where the limb ends, thus having no correlation with the dermatomal sensory distribution.Midline splitting - refers to an exact splitting of sensations in the midline, which is generally suggestive of a functional syndrome. Since there is overlapping of cutaneous branches of the intercostal nerves from the contralateral side at the midline, any organic hemisensory deficit would be paramedian and not extend till the midline. However, this sign also has its fallacy, as a thalamic stroke causing profound loss of all sensory modalities can cause a midline splitting. A reversible hypointensity of the contralateral thalamus and basal ganglia may be demonstrated on Single photon emission computed tomography in such patients.Laterality of symptoms - a systematic review has revealed that although there is a slight prevalence of left-sided symptoms over right, there may be a significant publication bias responsible for this. Thus, this sign is of not much value.Doctor Trickery- "say yes when you feel the touch and no when you don't" forms a common trickery for picking a functional deficit. Sensations may be tested with arms crossed behind or interlocked in front. ,,
Finally, though all the tests described help in differentiating an organic from a non-organic deficit, they cannot usually separate functional (or somatoform) symptoms from malingering (willfully produced for external gain) or factitious disorders (willfully produced for internal gain). Therefore, the final diagnosis has to be made keeping the overall clinical picture in mind and it has to be remembered that the presence of functional symptoms does not imply the absence of organic disease as both may coexist in the same patient.
|1||Sekerci R, Sarikcioglu L. Hoover's sign. J Postgrad Med 2013;59:216-7.|
|2||Reuber M, Mitchell AJ, Howlett SJ, Crimlisk HL, Grunewald RA. Functional symptoms in neurology: Questions and answers. J Neurol Neurosurg Psychiatry 2005;76:307-14.|
|3||Stone J, Zeman A, Sharpe M. Functional weakness and sensory disturbance. J Neurol Neurosurg Psychiatry 2002;73:241-5.|
|4||Stone J, Carson A, Sharpe M. Functional symptoms and signs in neurology: Assessment and diagnosis. J Neurol Neurosurg Psychiatry 2005;76:2-12.|